Resonator having distributed transconductance elements

Abstract

An apparatus comprises a resonator including a plurality of switched impedances spatially distributed within the resonator and a corresponding plurality of transconductance elements distributed within respective distances among the switched impedances. The resonator has a given desired resonant frequency and a given amplitude of response. Combined pairs of the switched impedances and transconductance elements have respective parasitic resonant frequencies which are higher than the given desired resonant frequency and have respective amplitudes of response which are lower than the given amplitude of response. The apparatus may be a voltage controlled oscillator or an active filter.

What is claimed is: 
     
       1. An apparatus comprising:
 a resonator comprising:
 a plurality of switched impedances spatially distributed within the resonator; and 
 a corresponding plurality of transconductance elements distributed within respective distances among the switched impedances; 
 
 wherein the resonator has a given desired resonant frequency and a given amplitude of response; 
 wherein combined pairs of the switched impedances and transconductance elements have respective parasitic resonant frequencies which are higher than the given desired resonant frequency and have respective amplitudes of response which are lower than the given amplitude of response; 
 wherein the switched impedances have different magnitudes and the transconductance elements are non-uniformly distributed within the resonator. 
 
     
     
       2. The apparatus of  claim 1  wherein the apparatus is a voltage controlled oscillator. 
     
     
       3. The apparatus of  claim 2  wherein the voltage controlled oscillator comprises at least one of a wide-tuning range oscillator, a digitally controlled oscillator and a millimeter wave oscillator. 
     
     
       4. The apparatus of  claim 1  wherein the apparatus is an active filter. 
     
     
       5. The apparatus of  claim 4  wherein the active filter comprises at least one of a switched impedance filter, a switched capacitor transconductance filter and a programmable narrowband band select filter. 
     
     
       6. The apparatus of  claim 1  wherein the switched impedances comprise a capacitor array. 
     
     
       7. The apparatus of  claim 6  wherein:
 one or more interconnects between capacitors in the capacitor array contribute respective parasitic inductances in the resonator; and 
 the transconductance elements are distributed within the capacitor array to reduce the parasitic inductances of the one or more interconnects. 
 
     
     
       8. The apparatus of  claim 1  wherein:
 the transconductance elements have associated therewith different transconductance values; 
 the switched impedances comprise capacitors having associated therewith different capacitance values; and 
 wherein the transconductance elements are distributed within the resonator such that the transconductance values are proportional to the capacitance values. 
 
     
     
       9. The apparatus of  claim 8  wherein a given distance between a given switched impedance and a given transconductance element is controlled based on a relationship between the capacitance value of the given switched impedance and the transconductance value of the given transconductance element. 
     
     
       10. The apparatus of  claim 1  wherein:
 the transconductance elements have associated therewith different transconductance values; 
 the switched impedances comprise inductors having associated therewith different inductance values; and 
 wherein the transconductance elements are distributed within the resonator such that the transconductance values are proportional to the inductance values. 
 
     
     
       11. The apparatus of  claim 10  wherein a given distance between a given switched impedance and a given transconductance element is controlled based on a relationship between the inductance value of the given switched impedance and the transconductance value of the given transconductance element. 
     
     
       12. The apparatus of  claim 1  wherein the transconductance elements are non-uniformly distributed within the resonator based on the magnitudes of the switched impedances. 
     
     
       13. The apparatus of  claim 1  wherein the transconductance elements are distributed based on a target narrowband bandpass transfer function. 
     
     
       14. The apparatus of  claim 1  wherein an operating frequency of the resonator is 20 gigahertz or greater. 
     
     
       15. The apparatus of  claim 1  wherein physical dimensions of the apparatus are greater than 1/100 of a wavelength of the apparatus. 
     
     
       16. The apparatus of  claim 1  wherein physical dimensions of the apparatus are greater than 1/1000 of a wavelength of the apparatus. 
     
     
       17. An integrated circuit comprising:
 a resonator comprising:
 a plurality of switched impedances spatially distributed within the resonator; and 
 a corresponding plurality of transconductance elements distributed within respective distances among the switched impedances; 
 
 wherein the resonator has a given desired resonant frequency and a given amplitude of response; 
 wherein combined pairs of the switched impedances and transconductance elements have respective parasitic resonant frequencies which are higher than the given desired resonant frequency and have respective amplitudes of response which are lower than the given amplitude of response; 
 wherein the switched impedances have different magnitudes and the transconductance elements are non-uniformly distributed within the resonator. 
 
     
     
       18. A voltage controlled oscillator comprising the integrated circuit of  claim 17 . 
     
     
       19. An active filter comprising the integrated circuit of  claim 17 . 
     
     
       20. The integrated circuit of  claim 17  wherein the transconductance elements are non-uniformly distributed within the resonator based on the magnitudes of the switched impedances. 
     
     
       21. A method comprising:
 forming a resonator comprising a plurality of switched impedances spatially distributed within the resonator; and 
 forming a plurality of transconductance elements within respective distances among the switched impedances; 
 wherein the resonator has a given desired resonant frequency and a given amplitude of response; 
 wherein combined pairs of the switched impedances and transconductance elements have respective parasitic resonant frequencies which are higher than the given desired resonant frequency and have respective amplitudes of response which are lower than the given amplitude of response; and 
 wherein the switched impedances have different magnitudes and forming the plurality of transconductance elements comprises non-uniformly distributing the transconductance elements within the resonator. 
 
     
     
       22. The method of  claim 21  wherein non-uniformly distributing the transconductance elements within the resonator is based on the respective magnitudes of the switched impedances. 
     
     
       23. The integrated circuit of  claim 17  wherein:
 the switched impedances comprise a capacitor array; 
 one or more interconnects between capacitors in the capacitor array contribute respective parasitic inductances in the resonator; and 
 the transconductance elements are distributed within the capacitor array to reduce the parasitic inductances of the one or more interconnects. 
 
     
     
       24. The integrated circuit of  claim 17  wherein an operating frequency of the resonator is 20 gigahertz or greater. 
     
     
       25. The method of  claim 21  wherein:
 the switched impedances comprise a capacitor array; 
 one or more interconnects between capacitors in the capacitor array contribute respective parasitic inductances in the resonator; and 
 the transconductance elements are distributed within the capacitor array to reduce the parasitic inductances of the one or more interconnects.